Re: bug?: git reset --mixed ignores deinitialized submodules

From: Stefan Beller <sbeller@google.com>
Date: Mar 13, 2017, 21:19 UTC
Message-ID: <CAGZ79ka=OwSWGDBqiZ5X9LvOXphFe5=QjmH9DoeWLu2svmVtyg@mail.gmail.com>
In-Reply-To: <1489430233.10192.56.camel@novalis.org>

Show 8 quoted lines

>> The change is not really lost, as you can get it via
>>
>>     git checkout HEAD@{1}
>>     git submodule update --init
>
> Sure, the commit isn't lost entirely.  But a mixed reset is often used
> to mean "go back to before I committed", and here, that's not precisely
> what's happening.

Well, you ran the deinit after the commit, so I don't think we expect to undo everything up to "just before the commit".

> In other words, it's not confusing to the user.

ok, great :)

Show 22 quoted lines

>
>> This works most of the time, but it is unreliable as the
>> submodule may have had some gc inbetween which
>> threw away important objects.
>
> Sure; that's a separate issue.
>
>> Steping back a bit, rereading the subject line,
>> what do you think is the bug here?
>>
>> * git-status not reporting about uninitialized submodules?
>
> Here, I think git-status is correctly reporting the state of the repo.
>
>> * git reset --mixed not touching the submodule worktree
>
> Yes, possibly.
>
>> * lack of --recurse-submodules in git-reset? (and that not
>>   being default, see prior point)
>
> Or possibly this.

Well even in this case a reset recursing into submodules doesn't change the (de-)init status of a submodule. All it would alter is the submodule HEAD pointing to, IMHO.

Show 5 quoted lines

>
>> * submodules being in detached HEAD all the time?
>
> In this case, the submodule is not initialized, so it is not in any
> state at all.

Oh right.

Show 6 quoted lines

>
>
> For me, the bug (if any) is the bad user experience of doing a mixed
> reset and expecting to be able to commit (possibly with some git-add
> operations) from there and get back something like the commit to which
> the user had git-reset.

Technically this is also doable,

    git reset --mixed HEAD^ # as in the original email
    git update-index --add --cacheinfo \
        160000,$(git -C .git/modules/sub1 rev-parse HEAD),sub1
    git add another_file
    git commit -m "recreate the commit"

>
> That's why I have the question mark there -- it's not clear that this
> is a reasonable expectation.

Fuzzing around with gitlinks that are non-populated submodules is a messy business.

So another way would be to populate the submodule manually

    GIT_DIR=.git/modules/sub1 \
    GIT_WORKTREE=sub1 \
    git checkout -f # implies last HEAD

and then continue in the superproject.

I am making up excuses for poor UX here, though. I do agree that the expectations may vary wildly because of poor UX in submodules.

Stefan